The free FocusWriter word processor aims at building a distraction free space for writing, without sacrificing the basic tools you need to finish your novel. It runs on Windows, Mac, and Linux operating systems.
The word processor fills your entire screen, escaping the magnetic lure of the Internet. It includes a number of features: spell check, live writing statistics, and writing goal functions. However, the “hide-away interface” allows you to keep the extra writing features off-screen–cutting out the crowded rows of icons that haunt Microsoft Word users.
Here’s more from the site: “FocusWriter is a fullscreen, distraction-free word processor designed to immerse you as much as possible in your work. The program autosaves your progress, and reloads the last files you had open to make it easy to jump back in during your next writing session, and has many other features that make it such that only one thing matters: your writing.” (Via Lifehacker)